Pencils and more especially cosmetic pencils are frequently produced either by a procedure in which a suitable cosmetic stick or lead material is extruded cold and glued into a grooved board portion using the method known from the manufacture of lead pencils, whereupon the board portion can be cut up lengthwise to form the finished pencils, or a procedure in which pourable cosmetic material is poured in a hot condition into prefabricated sleeve-like casing portions with a concentric hole therein, the stick material then being allowed to cool and harden in the casing portion.
In the first-mentioned extrusion procedure, it is only possible to use stick materials which result in relatively hard sticks as the sticks must remain handleable for further processing thereof. However, in relation to sticks for cosmetic pencils, that aspect involves a restriction in terms of the choice of extrudable textures, or it results in the pencil providing a relatively hard marking effect which is not desirable in cosmetic uses.
The above-mentioned pouring process on the other hand involves the problem that the process must use sleeve-shaped casing portions which are in a completely finished condition, that is to say which have been completely put into the desired shape and decorated. It will be appreciated that, in the event of such a pencil being rejected as defective, the processing costs involved in producing the casing portion in its completed form represent a considerable loss which thus has a major effect on overall production costs. Furthermore, when using casing portions comprising wood, wood substitutes or plastic material, roughness at the inside surface of the central hole in the casing portion result in the formation of gas bubbles when a hot cosmetic stick material is poured into the casing portion, due to the interaction between the hot cosmetic material and the material of the casing portion. The gas bubbles give rise in the finished stick to cavities which result in a reduction in the quality of the pencil such that in extreme cases the pencil has to be rejected and is thus a production loss. It is further possible that, in the liquefied condition of the stick material, components of that material may be absorbed by the material of the casing portion, and that can again result in a reduction in the quality of the stick material.
If cosmetic stick materials with volatile components such as for example volatile silicones, paraffins or the like are poured into casing portions of wood or wood substitutes, the inside surface of the hole of the casing portion has to be suitably coated or sealed off in order to prevent the volatile components from migrating or diffusing into the casing portion, as they would in turn result in undesirable changes in the quality of the pencil stick produced. For that reason it has not hitherto been readily possible to produce cosmetic pencils containing volatile components such as silicone oils, paraffins or the like, and to put them into intermediate storage over a prolonged period because the volatile components, in the storage situation, evaporate uncontrollably out of the stick materials, thus further resulting in an undesirable variation in the quality of the stick.
One form of a process for the production of a pencil stick, as is disclosed in DE 38 35 680 A1, involves using a mold comprising a plastic material, which is open in a slit-like configuration along at least a part of its peripheral surface. The mold preferably has a longitudinal slit extending over the entire length of the mold. Although it is possible in that way to introduce a stick material through the slit, the slitted open shape however means that it is not possible to prevent volatile components of the stick material evaporating uncontrollably out of same, particularly in a prolonged intermediate storage situation, and that once again, as indicated above, can result in an undesirable change in the quality of the stick.
The pencil which is intended in particular for cosmetic purposes and which has a stick produced by a casting procedure and which is firmly enclosed and held in position by a sharpenable casing portion of wood, as disclosed in DE 27 18 957 C3, provides that the casing portion of wood is in the form of a one-piece tubular member whose inside surface has a coating thereon, which acts as a barrier to prevent components of the stick material from penetrating into the casing portion. The stick material is poured into the tubular casing portion, forming an exposed tip for the pencil stick.
Another cosmetic pencil, as disclosed in DE 27 59 610 C2, has a pencil stick which is produced by a pouring process and a casing portion formed by a tubular member. The casing portion firmly embraces the stick, while both the casing portion and the stick can be sharpened to a point. The exposed tip of the pencil stick has a conical surface while the end of the casing portion is frustoconical so as to be in flush adjoining relationship with the conical surface of the exposed tip of the stick. The casing portion is a seamless plastic member into which the stick material is poured, forming the exposed tip thereof. The conical surface of the pencil tip and also a rounded-off end on the tip are formed when the stick material is poured into the casing portion. The inside surface of the casing portion may again be provided with a coating to prevent stick material or components thereof from diffusing into the casing portion. A similar form of cosmetic pencil is also to be found in DE 27 59 856 C2.
A writing pencil or crayon, as disclosed in DE 40 03 288 A1, comprises a sheathing and a stick disposed therein, the sheathing entirely or predominantly consisting of papier-mache, wood dust and/or mechanical wood pulp. DE 40 03 289 A1 discloses a writing pencil or crayon having a casing portion consisting of a sheathing of layers of paper, wood or plastic material, in sheet or foil form, and a lead or stick disposed therein, or another writing agent and/or writing agent storage device, and possibly a clamping device for holding the lead or stick and/or a feed device for advancing the lead or stick and/or other components. As indicated above, the sheathing which forms the casing portion entirely or predominantly consists of layers of paper, wood and/or plastic material in sheet or foil form, which are laminated one over the other or which are rolled together. However that pencil cannot be employed for cosmetic purposes.